US3875501A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse width modulation type resistance deviation measuring apparatus
Assignee: Yokogawa Electric Corp
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Filing: 1973-11-13
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Granted: 1975-04-01
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Expires: 1993-11-13
Abstract
Abstract A resistance deviation measuring device, of the type used for measuring a temperature with a temperature-sensitive resistance and for obtaining a digital signal representing the measured temperature, is characterized by a simple and reliable arrangement operating without precision power sources but still with the characteristics of a pulse width modulating type analogdigital converter, i.e., with an integrator receiving as its input the sum of an unknown analog signal and either a positive or a negative reference signal, means for comparing the output of the integrator with a comparison signal, e.g., a sawtooth signal, and for selecting between the positive and negative reference signals as a result of the comparison to zero the average value of the input to the integrator, and with digital counting means for digitally measuring a time interval ended by the comparing means. The resistance deviation measuring device of the present invention connects the unknown temperature-sensitive resistance to a reference resistance in series, and uses a series voltage source to generate the same current flow through both resistances to produce an unknown voltage respectively. The unknown analog signal is formed by a circuit which applies the difference between the unknown voltage and reference voltage to the integrator input. The positive and negative reference signals are formed by a circuit inverting the reference voltage, and applying either the inverted or non-inverted reference voltages to the integrator input to be summed with the analog signal. The digital counting means measures the difference of the comparator pulse width from a half-cycle, and thus digitally represents the deviation of the unknown resistance from the reference resistance.
Inventors
- 👤 Eiji Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:51
CPC Classifications
G; G01; G01R; G01R27/00; G01R27/02; G01K; G01K1/00; G01K1/02; G01K1/028; H; H03; H03M; H03M1/00; H03M1/12; H03M1/50; H03M1/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
236 words
A resistance deviation measuring device for determining the deviation of an unknown resistance from a predetermined resistance value by means of pulse width modulating type converter means having integrating means arranged to receive as inputs the sum of an unknown analog signal and either a positive or a negative reference signal, means for comparing the output of the integrating means with a comparison signal and for selecting between the positive and negative reference signals as a result of the comparison to zero the average value of the input signals to the integrating means, and having digital counting means digitally measuring a time interval determined by the comparing means, the resistance deviation measuring device being characterized by: a reference resistance; means for generating the same current flow through the unknown resistance and the reference resistance to develop thereacross an unknown voltage and a reference voltage respectively; means for applying the unknown voltage developed across the unknown resistance to the input of the integrating means to obtain the unknown analog signal input thereto; means for developing both of the positive and negative reference signal inputs to the integrating means from the reference voltage developed across the reference resistance; and switch means responsive to the comparing means for applying said positive and negative reference signal inputs to the integrating means, whereby the digital counting means digitally represents the deviation of the unknown resistance from a predetermined resistance value. Pg,15
Claim 2
Dependent Claim
236 words
A resistance deviation measuring device for determining the deviation of an unknown resistance from a predetermined resistance value by means of pulse width modulating type converter means having integrating means arranged to receive as inputs the sum of an unknown analog signal and either a positive or a negative reference signal, means for comparing the output of the integrating means with a comparison signal and for selecting between the positive and negative reference signals as a result of the comparison to zero the average value of the input signals to the integrating means, and having digital counting means digitally measuring a time interval determined by the comparing means, the resistance deviation measuring device being characterized by: a reference resistance; means for generating the same current flow through the unknown resistance and the reference resistance to develop thereacross an unknown voltage and a reference voltage respectively; means for applying the unknown voltage developed across the unknown resistance to the input of the integrating means to obtain the unknown analog signal input thereto; means for developing both of the positive and negative reference signal inputs to the integrating means from the reference voltage developed across the reference resistance; and switch means responsive to the comparing means for applying said positive and negative reference signal inputs to the integrating means, whereby the digital counting means digitally represents the deviation of the unknown resistance from a predetermined resistance value. Pg,15
Claim 3
Dependent Claim
61 words
A resistance deviation measuring device as claimed in claim 1 wherein the means for applying the unknown voltage developed across the unknown resistance to the input of the integrating means comprises means for obtaining the difference between the unknown voltage and the reference voltage and for applying said difference to the input of the integrating means to form said analog signal.
Claim 4
Dependent Claim
73 words
A resistance deviation measuring device as claimed in claim 1 wherein the means for developing the positive and negative reference signal inputs to the integrating means comprises means for inverting the polarity of said reference voltage and wherein the switch means, controlled by said comparing means, selectively applies either the noninverted reference voltage or the inverted reference voltage to the input of the integrating means to form said positive and negative reference signals.
Claim 5
Dependent Claim
70 words
A resistance deviation measuring device as claimed in claim 1 wherein the time interval measured by the digital counting means is initiated a predetermined amount of time after the reference signal is changed by the comparing means which is equal to one half the period of one cycle of operation of the comparing means, whereby the digital counting means represents the deviation of the unknown resistance from the reference resistance.
Claim 6
Dependent Claim
35 words
A resistance deviation measuring device as claimed in claim 4 wherein the unknown resistance is a temperature-sensing resistance, and wherein the reference resistance is provided with a predetermined resistance value representing a predetermined temperature value.
Claim 7
Dependent Claim
46 words
A resistance deviation measuring device as claimed in claim 1 wherein said reference resistance and said unknown resistance are connected in series with each other, and wherein the means for generating the same current flow through the unknown resistance and reference resistance comprises a voltage source.
Claim 8
Dependent Claim
119 words
A resistance deviation measuring device as claimed in claim 6 wherein the junction of the unknown resistance and reference resistance is connected to the ground level of the integrating means, and wherein the means for applying the unknown voltage across the resistance to the input of the integrating means comprises a first coupling circuit connected to the unknown resistance opposite said ground connection and connected to the input of the integrating means and a second coupling circuit connected to the reference resistance opposite said ground connection and to the input of the integrating means, said two coupling circuits forming the analog input voltage applied to the integrating means as the difference between said unknown voltage and said reference voltage.
Claim 9
Dependent Claim
26 words
A resistance deviation measuring device as claimed in claim 7 wherein said first and second coupling circuits each comprise inverting means in series with resistance means.
Claim 10
Dependent Claim
112 words
A resistance deviation measuring device as claimed in claim 6 wherein the junction of the unknown resistance and reference resistance is connected to the ground level of the integrating means, and wherein the means developing the positive and negative reference signal inputs to the integrating means comprises a coupling circuit connected to the reference resistance opposite said ground connection and connected to the input of the integrating means, said coupling circuit comprising a resistance in series with the integrating means and having means for inverting the polarity of the reference voltage, said switch means selecting between the two polarities of reference voltage and applying them to the input of the integrating means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |